Ravens: the new desert blight

Monday

Mar 14, 2011 at 6:54 AMMar 27, 2013 at 7:49 AM

NATIONAL PARK SERVICE

Are you outside? Look up, look around you, and if you don't spot one immediately, wait a few minutes. Your chances of seeing a common raven are very good. These jet-black birds with glossy, iridescent feathers, chisel-shaped black bills and wingspans of up to 4 feet are ubiquitous in the Mojave and Colorado deserts.

But this wasn't always the case. Ravens were uncommon in the California deserts in the first half of the 20th century; wildlife biologists now estimate that raven populations have increased here by about 1,000 percent in the past 35 years. But how?

Although the question cannot be answered with any finality, much of the raven's success seems to hinge on its innate intelligence and its ability to exploit conditions provided by human habitation. Wherever people are, ravens thrive. They are world-class opportunists.

It has been said that more has been written about the raven than about any other bird. Even before recorded history, Native Americans told many stories about the raven, the majority of which characterized it as a mischievous and clever animal. Perhaps ravens fascinate us because they have been observed playing with sticks and passing stones to each other, and they have been taught to count, mimic human speech and to read the face of a clock. Ravens reportedly mate for life (although this statement has been contested by some observers) and they have an extraordinarily diverse vocabulary of vocalizations.

Over the course of the past two decades, ravens have earned a villainous reputation among naturalists in the California deserts — they have been identified as one of the main predators of desert tortoise, Gopherus agassizii, hatchlings, a species listed as "threatened" on the federal Endangered Species List. Early efforts made by several agencies to mitigate the raven's impact on desert tortoises have had limited success. Raven populations continue to increase while tortoise populations remain in decline.

In order to help restore the balance between ravens and tortoises, and between ravens and the other species they affect, we can become aware of some of our current practices and change them. These are some of the things we might do to help control raven populations: